Merck Manual

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Professional Version

Breeding Soundness Examination of Bucks


Sylvia J. Bedford-Guaus

, DVM, PhD, DACT, Peekskill-Cortlandt Veterinary Hospital, Westchester Veterinary Associates

Reviewed/Revised Apr 2014 | Modified Oct 2022

Breeding soundness examination in bucks has not been detailed to the extent that it has in rams. The testes should be palpated carefully. Brucella ovis infection is rare, but sperm granulomas are frequently related to the polled condition; these are most often found in the head of the epididymis. Cryptorchidism is also common and heritable; as in other species, cryptorchid bucks should not be used for breeding. Testicular degeneration is a common cause of fertility loss in older bucks. Semen is collected using an artificial vagina (AV); bucks are easily trained for this method and do not tolerate an electroejaculator. An electroejaculator might be used only if the buck is sedated. Parameters for semen evaluation are similar to those for rams. Because the ejaculate is typically collected with an AV, sperm production may be measured rather than estimated from scrotal circumference. Semen volume should be 0.5–2 mL, and concentration 1.5–4 billion sperm/mL.

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